Motions in air and water are a concentrated form of renewable energy resources that hold great opportunities to provide energy in an environmentally friendly way. And humans have used these resources for thousands of years. The energy has partly been absorbed and converted by vertical axis power plants, meaning that the part of the power plant that absorbs the energy is located on an axis that is vertically directed, and partly by horizontal axis power plants, meaning that the part of the power plant that absorbs the energy is located on an axis that is horizontally directed. The power output of a turbine is directly related to the sweep area of its turbine. And the sweep area is roughly the area that the turbine is capable of extracting the energy from.
However it could in many different situations be an advantage to alter the sweep area of a turbine. For example one could lover the friction losses from a spinning flywheel storing energy in form of rotation or in extreme weather where you would like to absorb less energy.
A previous power plant that has solved some interval of these problems is the patent application US20080187432, which comprises a vertical axis wind turbine having a plurality of blades spaced from a rotatable around a rotor shaft vertical to the ground. U.S. Pat. No. 4,775,340 discloses a similar example of this wherein a turbine apparatus for providing support peripherally for a turbine rotor having either a vertical or horizontal axis of rotation.
Even though the above described arrangements may alter the sweep area is there still a desire for a dynamic turbine which is constructed to be able to efficiently change its configuration.